With the rapid evolution of radiation-based imaging technologies including, for example, CT technologies, and growth of their new clinical and industrial applications, fidelity of image especially under a low radiation dose attracts more attentions.
Image processing may include, for example, contrast enhancement, a denoising operation, or the like, or any combination thereof. The image quality may depend on, for example, the specific contrast enhancement mechanism or the noise model. The image quality may be sensitive to noise when low radiation dose is taken into account.
Image reconstruction may introduce artifacts to generated CT images. Generally, an object being exposed to X-ray during the forward projection may be divided into voxels, for example, cubic or cuboid voxels. The contribution of a certain voxel to detector cells may derive from, for example, the voxel value and a relevant contribution factor. Relevant contribution factor may be determined by the location of the voxel in a coordinate system of the detector cells. When the object is divided into voxels, the voxel values at the boundaries between the two voxels may be discontinuous, and the iteration process of forward and backward projection may bring about the boundary blurred effect.